GB385225A - Improvements in or relating to change-over keys or switches for telephone exchanges and the like - Google Patents

Abstract

385,225. Retractive switches switches held set and freed mechanically. RICHTER, M. B., 7, Amaliegade, Copenhagen. June 29, 1932, No. 18387. Convention date, March 10. [Class 38 (v).] In a change-over switch, more particularly for telephone exchanges having a shifting member co-acting directly, or indirectly with contact springs and capable of being swung to either side from a midposition, the shifting member is mounted to rock around one or the other of two parallel axes of rotation. The shifting member or lever e, Figs. 1 and 2, carries two parallel pivot studs movable at either end in slots k and notches l in a fixed frame a and in the midposition of the lever held at the end of the slots and notches by a spring m secured by a screw n to the frame a and acting on insulated rollers o on the studs j. A cam or groove guide prevents vertical movement of the lever and allows the lever to swing about either axis and as shown comprises a tongue p on the lever engaging in the mid-position of the lever the point of a tongue q on the frame a. Semicircular cam-pieces g on the lever are adapted to penetrate like a wedge between the bent ends h of contact springs d to close or interrupt the contacts. The end m<1> of the spring m is bent so as to engage above a roller o and maintain the lever in the left extreme position. In the right extreme position the other end of the spring returns the lever to mid-position when released. In the modification shown in Fig. 6, the lever indirectly operates the horizontally positioned contact springs d<1> by means of cams g<1>, g<2> operating sliding members r<1> maintained in position by locking plates w<1> and urged upwards by springs x<1> between the sliding members and locking plates. The plates are locked by means of apertures on fixed studs s which guide the sliding members. Rollers t<1> on the sliding, plates are pressed against the cams and maintain the operating lever e<1> in mid-position. The cam g<1> is shaped to maintain the lever in one extreme position. The lever is returned by spring action from the other extreme position when released. Insulated teeth u<1> on the sliding members engage lateral fins v to operate the contacts.. Vertical' movement is prevented by slot z and screw y. More than two cams and return springs may be used.